Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a storage medium.
Description of the Related Art
In recent years, there is proposed a camera called “light field camera” as a camera capable of changing a focus position after photographing. This camera obtains, in addition to positional information indicating a position on an image pickup plane into which a light beam reflected from an object is entered, light beam information including angular information indicating an incident angle. The light beam information is called “light field data” (hereinafter referred to as “LF data”).
In Ren Ng et al. “Light Field Photography with a Hand-held Plenoptic Camera”, Stanford Tech Report CTSR 2005-02, there is disclosed an image pickup apparatus in which a large number of microlenses are arranged between a main lens and an image pickup element. The image pickup apparatus is configured to separate the entered light beam by the microlenses and receive each of the light beams obtained through the light separation by the image pickup element, to thereby obtain the LF data. In the above-mentioned literature, there is also disclosed a refocusing technology for computing image data on a virtual imaging plane by using the LF data, to thereby generate an image in a focus position different from a focus position when photographing.
In U.S. Pat. No. 4,410,804, there is disclosed an image pickup apparatus using a two-dimensional image pickup element in which one microlens and a plurality of divided photoelectric converters are formed for one pixel. The divided photoelectric converters are configured to receive, through one microlens, light passing through different pupil part regions of an exit pupil of a photographing lens. Photoelectric conversion signals received from those respective divided photoelectric converters allow a plurality of parallax images corresponding to the divided pupil part regions to be generated. Through use of the obtained plurality of parallax images, a portion to be focused on is subjected to combining processing, to thereby allow the focus position to be changed after photographing.
Such a light field processing technology as described above can also be applied to a moving image photographing. In reproduction of data having a moving image format, search reproduction such as fast-forward or rewinding, which is not conducted in reproduction of data having a still image format, may be conducted. A light field image may be refocused by a user, and a refocused image having a small depth of field is often used as the light field image. This raises a problem in that, when the search reproduction of a moving image is conducted with the image having a small depth of field, the moving image is poor in visibility for the user, and a desired scene is hard to find.